“There are three areas in which the person who would be wise and good must be trained. The first has to do with desires and aversions…the second has to do with impulses to act and not to act…and the third has to do with freedom from deception and composure and the whole area of judgement. Of these areas, the chief and most urgent is the first which has to do with the passions, for strong emotions arise only when we fail in our desires and aversions.”
Epictetus, Discourses.

Master your desires – recognise which things you like and which you don’t like. Notice your emotional reaction to these things and then be prepared for when they are likely to occur again. You cannot stop them from happening – that is not in your control – but your choice of reaction is in your control. The more options you have available to you, the more likely you are to make a ‘good’ judgement.